1. Field of the Invention
The present invention relates to a recording tape cartridge which rotatably accommodates a single reel onto which a recording tape such as a magnetic tape or the like is wound.
2. Description of the Related Art
Recording tapes such as magnetic tapes and the like are used as external recording media for computers and the like. Recording tape cartridges that accommodate a single reel on which a recording tape is wound take up little space when stored and can record large amounts of information, and are employed as such recording tapes.
A recording tape wound on a single reel is rotatably accommodated in a case of such a recording tape cartridge. The case is formed by joining an upper case and a lower case, which are each formed of resin material. An opening aperture is formed in this case. The recording tape is drawn out through this opening, and wound on a drive device side winding reel.
Accordingly, in order that dust and the like does not ingress through the opening aperture and adhere to the recording tape, the opening aperture is opened and closed by a door, which is a covering member. Specifically, the opening aperture is closed by the door when the recording tape cartridge is not in use, and the door displaces or rotates to open up the opening aperture when the recording tape cartridge is to be used.
As a recording tape cartridge that is provided with such a door, a well-known structure includes: an opening aperture formed in a side wall of a case along a loading direction into a drive device; a door which slides along the direction of loading at an inner side of the side wall for opening and closing the opening aperture; a spring which urges the door in a direction of closing the opening aperture; and an operation portion provided at the door, which is engaged with an opening/closing member of the drive device and slid in a direction of opening the opening aperture by an operation of loading the case into the drive device.
In this structure, the operation portion provided at the door is engaged with an opening member fixed in the drive device (which moves relative to a bucket of the drive device) and slid relative to the case to open the opening aperture by a simple operation of loading the case (i.e., the recording tape cartridge) into the drive device, that is, by moving the case, which has been loaded on the bucket, in the loading direction together with the bucket. Therefore, it is sufficient simply that the opening member is fixedly disposed at a position that enables engagement with the operation portion. Thus, structure thereof is simple.
However, in a conventional recording tape cartridge as described above, when the operation portion of the door engages with the opening member of the drive at a time of opening the opening aperture, a torque (or movement of rotation) acts around the point of engagement, the case (i.e., the recording tape cartridge) rotates around the point of engagement, and there is a problem in that the case becomes inclined relative to the direction of loading. In particular, because the opening is opened against urging force of the spring, this torque (pushing force in the loading direction) is large, and the case is more susceptible to inclination in the drive device.
As the case is pushed into the drive device in this state, the case may scrape against the drive device, the case may be damaged, abrasion dust may be generated in the drive device, and the case may become stuck in the drive device.
Accordingly, in order to counteract this torque, a structure has been considered in which an engaging member provided at the bucket of the drive device engages at a position on a face at a leading end side in the loading direction of the lower case (a front face), which position is separated from the side wall in which the opening is formed, and this state of engagement is maintained while the case moves in the loading direction with the bucket and the opening aperture is opened.
However, with a case formed by joining up an upper case and lower case formed of resin material as described above, a draft angle for die cutting, after outer faces including the front face have been formed as design surfaces on which texturing processing or the like is carried out, is large, and dimensional accuracy is low. When the engaging member of the drive device engages at the front face of such a case, positional accuracy of the case on the bucket is low and, even though the torque is counteracted, the case will be slightly angled on the bucket while the case is loaded into the drive device. This may lead to smooth movement of the door (that is, the operation of opening the opening aperture) being hindered, and there is a problem in that force components may act in directions other than the direction of opening the opening aperture.
Further, the front face of the lower case is angled downwards with respect to the direction of loading because of the aforementioned draft angle. Therefore, because of a reactive force when the torque is counteracted, force acts on the case in a direction of lifting up the front portion of the case. As a result of this force, the case is angled in a vertical direction with respect to the loading direction, and this also may lead to smooth movement of the door being hindered.
In consideration of the circumstances described above, an object of the present invention is to provide a recording tape cartridge which can avoid inclination of a case with respect to a loading direction when a door is moved in an opening direction by an operation of loading the cartridge into a drive device.
In order to achieve this object, in accordance with a first aspect of the present invention, a tape cartridge insertable into a tape drive that includes an opening member and an engaging member, which are capable of operatively engaging with the tape cartridge at a time of insertion of the tape cartridge, and carries out at least one of reading and writing of data is provided. This tape cartridge includes: (a) a case; (b) a tape access opening provided at one side relative to a center line of the case, the center line extending in a direction of the insertion of the cartridge; (c) a covering member which is reciprocally moveable between a closed position for closing the tape access opening and an open position for opening the tape access opening; (d) an operation portion which cooperates with the opening member of the tape drive at the cartridge insertion time and moves the covering member in the direction of the open position; and (e) an engagement portion provided at the other side relative to the centre line of the case and capable of cooperating with the engaging member of the tape drive at the cartridge insertion time.
Preferably, the case recess portion is capable, at the cartridge insertion time, of functioning to counterbalance movement of the covering member in the direction of the closed position.
Further, in accordance with another aspect of the present invention, a tape drive for carrying out at least one of reading and writing of data at an insertable and removable tape cartridge is provided. This tape drive includes: (A) an opening member capable of operatively engaging with the tape cartridge at a time of insertion of the cartridge; and (B) an engaging member capable of operatively engaging with the tape cartridge at the cartridge insertion time, and (C) the tape cartridge includes: (a) a case; (b) a tape access opening provided at one side relative to a center line of the case, the center line extending in a direction of the insertion of the cartridge; (c) a covering member which is reciprocally moveable between a closed position for closing the tape access opening and an open position for opening the tape access opening; (d) an operation portion which cooperates with the opening member of the tape drive at the cartridge insertion time and moves the covering member in the direction of the open position; and (e) an engagement portion provided at the other side relative to the centre line of the case, which cooperates with the engaging member of the tape drive and is capable of implementing a counterbalancing function with respect to movement of the covering member in the direction of the closed position.